Apparatus for thermochemically cutting gears



OC- 30, 1951 D. A. scHRocK APPARATUS FOR THERMOCHEMTCALLY CUTTING GEARs Filed Jan. 19, 1948 3 Sheets-Sheet l LVIII/1 I I l l l l 1 l L as las 'lg/64 Daniel "A. Schrovck Fig. 8

IN VEN TOR.

Oct. 30, 1951 D. A. scHRocK 2,573,653

APPARATUS FOR THERMOCHEMICALLY CUTTING GEARS Filed Jan. 19, 1948 5 sheets-sheet 2v l 2o k12 I @n Dan/'el A .Sc/:rock

INVENToR.

BY WwW-Mm Oct. 30, 1951 D. A. scHRocK APPARATUS FOR THERMOCHEMTCALLY CUTTING GEARS 3 Sheets-Sheet 3 Filed Jan.

brc Movement Dan/'el A Schrock INVENTOR.

Patented Oct. 30, 1.951

APPARATUS FOR THERMOCHEMICALLY CUTTING GEARS Daniel A. Schrock, Boise, Idaho, assignor to Idaho Sprocket and Machine Works, Boise, Idaho, a

copartnership Application January 19, 1948, Serial No. 3,116

6 Claims. (Cl. 266-23) This invention appertains to novel and useful improvements in an Iapparatus for thermochemically treating materials, preferably metallic.

An object of this invention is to thermochemically remove material from sheet stock in order to form gears and the like therefrom.

Another object of this invention is to thermochemically cut a metallic sheet by means of moving a torch orbcally in an undulated travel in order to form. gear teeth.

Another object of this invention is to decrease the speed of the torch while in the undulated portion of the orbit of travel to eicaciously and completely cut the metal blank or stock.

Another object of this invention is to selectively control the speed of a sleeve relative to a concentric shaft, which sleeve has a torch associated therewith and which shaft urges the torch in devious travels in order to form gear teeth and the like.

A still further object of the invention is to control the speeds of the shaft and torch through the medium of a circuit breaker including a pair of elements which are operatively associated with the shaft and sleeve respectively, which control is ultimately afforded through the medium of an electrical bypass to the motor which introduces additional resistance in the electrical circuit.

Another purpose of this invention is to simultaneously urge a torch carriage in a selected direction by resilient means and also urge a cam follower against a cam, which cam is rigidly associated with the said shaft.

Another object of this invention is to vary the speeds of the shaft and sleeve through the medium of a mechanical variable ratio transmission having a driven and driving side, the driven side being also utilized for turning the shaft while the driving side is mechanically connected with the sleeve.

Ancillary objects and features of novelty will become apparent to those skilled in the art in following the description of the preferred form of the invention, illustrated in the accompanying drawings, wherein;

Figure 1 is a sectional view of the preferred form of the invention, showing the same in use with a typical work piece or blank;

Figure 2 is a transverse sectional view taken substantially on a line 2 2 of Figure l and in the direction of the arrows;

Figure 3 is a transverse sectional View taken substantially on a line 3-3 of Figure 1 and in the directionof thearrows; f

Figure 4 isa'transversesectionalview takenv substantially on a line 4--4 of Figure 1 and in the direction of the arrows;

Figure 5 is a sectional View illustrating the,

torch and torch support structure, taken substantially on a line 5 5 of Figure 1 and in the direction of the arrows;

Figure 6 is a sectional view of a typical mechanical variable gear ratio transmission utilizedv in association with the invention;

Figure '7 is a schematic view showing particularly the torch travel on a work piece or blank; and,

Figure 8 is a wiring diagram showing the simplied electrical circuit utilized in association with the invention.

There are many types of devices for cutting gears or the like which may be classified under several broad headings. There are those in which the work piece is moved while the torch is held4 substantially stationary and those which revolve or otherwise move the torch, the work piece remaining stationary. The present invention re lates to an improved method and apparatus for cutting the gears, falling under the latter class.

It is one of the prime purposes of the invention to supply a practical apparatus adapted for use in association with flat sheet stock wherein manyv Process The preferred process or method of thermo? chemically removing metal includes various steps.v

A substantially flat work piece or stock l0 may be supplied on a suitable support (not shown). beneath an apparatus for performing cutting op erations thereon.

A torch is maintained in spaced relation from the work piece and is moved in a substantially cir'` cular or arcuate travel with periodic deviations in the circular path. Otherwise spoken, the said torch assumes an orbically influenced travel in an undulated path in order that gear teeth might be formed from the blank. As theY torchrassumes its orbical travel the speed of the torch is relatively high, however, as it proceeds lto form thev undulated portion of the travel, .thespeed is decreased in order to form complete and I"Galilea- Vthe like.

Means for supporting and actuating a sleeve and concentric shaft A frame generally indicated at I is supplied for support purposes. angle iron construction or the like and is adapted to be secured to a suitable anchor member suchv as a ceiling or the like. Wherever convenient and This frame may be of necessary platforms I2, I4 and` I6, respectively, g

form a part of the frame for journaling various and sundry elements therein.

A bracket I8 is attached to the said platform I2 through the medium of an angle iron member 28 and suitable, conventional bolts, rivets or A suitable prime mover such as the motor 22 illustrated in Figure 1, is attached to the bracket I8 and a coupling 24 is secured to the power shaft associated therewith. A suitable reduction gear box 261s also secured to the said bracket I8 and is juxtaposed relative to the motor 22.

Attention is now directed to Figure 2 wherein there is disclosed a gear 28 which is rigidly secured to the shaft 30 extending from the said gear reduction means 26. A plurality of idler gears 32, 34, 36 are journaled on the said platform I2 by means of conventional stub shafts. These idler gears are enmeshed and driven by t e said gear 28. It willbe noted -at this point that l the gears aforementioned are detachable innature in order that gears of various descriptions may be substituted therefor if found desirable such as to increase or decrease the gear ratio further.

A gear 88 is rigidly secured to the shaft 40 which is also rigidly secured to the said gear 36. Through this medium the said gear 38 is rotated upon movement of the said gear 36. Further, an additional gear 42 is secured to a shaft 44, which shaft extends through the platform I2 and terminates in a gear box 46. The shaft 44 is obviously associated with the driving side of the. gear box or mechanical variable ratiotransmission thereinLwhile the shaft 48 is associated with the driven side of the transmission.

The said gear box 46 contains a transmission which is purely conventional in nature, being utilized with small lathes and being capable of a 56| gear reduction by manipulation of the control rods 50 and 52, respectively.

A sleeve 54 is journaled in conventional antifriction bearings 56 and 58, respectively, which are seated in suitable receptacles 60. These receptacles are supplied in suitable apertures in the platforms I4 and I6 by any suitable means such as the bolts 62, illustrated in Figure 1.

A concentric shaft 64 is rotatively received in the bore of the sleeve 54 and terminates at one end in the said gear'32. A suitable cap screw 66 may be secured to a threaded end portion of the said` shaft 64 for maintaining this gear 32 in place.V Further, a spacing collar 68 maybe supplied beneath the said gear 32, resting on the inner race of a conventional anti-friction bearing 10, which is in turn seated in a receptacle 12 forming a portion of the platform I2.

Y It may now be seen that upon rotation of the VgearfZIl as innuenced by the torque supplied byv the motor (22,7 the `concentric shaft 64 will alsoy `be rotated.V I; .-1

The driven shaft 48 extending from the driven side of the variable speed transmission has a gear I4 secured thereon which is meshed with a relatively large gear 16, which in turn is secured to the said sleeve 54 through the medium of a conventional nut I8 and pin construction. It may now be seen that the relative rotation of the shaft 64`and sleeve 54 may be regulated through the medium of either replacement of idler gears or manipulation of the handles 58 and 52 to employ various gearratios in the conventional transmission.

The lower portion of the said tube 54 is journaled inthe said platform I6 through the medium of the conventional anti-friction bearing 58 as described above. A conventional nut 80 is threadedly received on an enlarged portion 82 of the said sleeve 54 and the nut engages the inner race of the said anti-friction bearing 56. At the extreme end of the sleeve and more specifically the enlarged portion 82, there is supplied a flange A84 with a plurality of apertures (unnumbered) therein. Further, a conventional anti-friction bearing 88 is supplied in an enlarged bore at the terminal of the sleeve 54 for assisting in journaling the said shaft 64 therein.

M cans for increasing and decreasing the relative Y speed of the shaft and sleeve Y motor 22 and on the proper electrical polar connection.

' A bypass conductor 98 bridges the conductors 90 and 96 and has a rheostat or other resistor |00 therein. l

In operation of the rotary switch including the contacts 92 and 94, respectively, it is quite apparent that the current for actuation of the motor 22 is supplied selectively through the switch and through the resistor |08. When the current is supplied directly through the switch to the motor, a greater speed thereof is effected and while the current is supplied to the resistor |00, a relatively lower speed of the motor is produced. This of course, imparts various speeds to the sleeve 54 and the shaft 64.

The specific structure ofl the said switch may be seen best in Figure 3 wherein a cam |02 is attached to the said shaft 64. Attached to a suitable post |04 is a lever I 06." The said post |04 is rigidly associated Vwith said gear I6 and is.of course, rotatable therewith. The cam follower 168 is secured vto the said lever .|06 andcured't'o Va suitable bracket YI I4 which is in' turn secured to the said large *gear 16. Asvthe shaft` 64..V andfsleevelif54 lflare I'rotatede relative tdi-each other, the contacts 92 and 94 will be intermittently engaged and disengaged as the cam |02 imparts lateral movement to the pivoted kconnection |08 of the members |06 and ||0 thereby actuating the switch blade ||2 due to the above described structure. By this expedient the motor 22 is supplied varying amounts of current for automatic variations in speed.

M eans for supporting a torch A torch is supplied with suitable inlet conduits |24 and |26 for conducting an oxidizable material such as air and acetylene. The various rotations and speeds of the shaft and sleeve 64 and 54, respectively, are transmitted through a mechanism for moving the torch |20 orbically in an undulated path, thereby forming gears from the flat metal stock |0. A housing |28 is attached to said flange 84 through the medium of conventional bolts |30 or rivets. Through this expedient it is readily apparent that upon rotation of the sleeve 54, the housing |28 will also be moved in a rotative manner. A plate |32 is rigidly attached to the said housing |28 through the medium of the bolts |34 and this plate is of course rotatable with the housing and sleeve 54. In order to center the work and regulate the torch for the desired size of gears to be cut, a curved arm |38 is attached to the plate |32. This arm has its point terminating in alignment with the longitudinal axis of the said shaft 64. Through this expedient the distance between the torch and the pointer may be measured in order to determine the radius of the gear to be cut.

Pairs of slots |40 and |42 respectively are Aprovided on and under the said plate |32 in order to accommodate rollers |44. These rollers are attached to suitable brackets |46 and |48, respectively, which form a portion of a carriage generally indicated at |50. It will be noted that the travel of the carriage is limited by the confines of the said slots |40 and |42 respectively, and the said rollers may be connected by suitable, conventional shafts |52.

Attention -is now directed to Figure 5 wherein the specific means for actually supporting the torch per se is illustrated. A sliding block |54 is provided with a dovetail slot |56 which is slidably received by a dovetail tongue |58, depending from a bracket |60. A suitable set screw |62 extends through the sliding block |54 and frictionally engages the dovetail tongue |58 for locking purposes. Further, a retaining bolt |64 extends through another sliding block |66, which pivot pin terminates in a base plate |68. The said base plate has a circular bearing element |10 depending therefrom which terminates in a suitable recess in the element |60. Set screws |12 and |14 respectively, are provided in the plate or element which operatively engage the tongue or bearing member |10 in order to restrict the rotation of the plate |60 and therefore the torch |20 in travel.

The said sliding block |66 is provided With shoulders |80 and |82 respectively, which seat on suitable flanges' or tracks |84 and |86 formed in the beam |88. By this means the torch may be regulated in its adjustment both toward and away from the pointer |38 and also rotated about the axis of the pin |64 for further adjustment. Any suitable means may be utilized for attaching the conventional split bearing |90 which maintains the torch |20 to the sliding block |54. The

6;" illustrated means includes a shank |92 which has threaded connections.

Further, a mixture control knob |94 may be used in association with the conventional valve case or housing |06 illustrated in Figure 1.

The torch |20 being rotatable with the shaft |54 assumes a particular generally circular orbit and various adjustments may be eifected by manual manipulation of the torch due to the adjustable structure herein described.

Means for urging the carriage |50 reciprocatively is provided. Through this expedient and due to the timed relative movement of the shaft 64 and sleeve 54, the gear teeth of various descriptions may be formed from the sheet metal blank I0. The preferred means for performing this function may be seen best in Figures l and 4 wherein the bracket |48 is illustrated as substantially U-shaped and has an extension 200 projecting therefrom. This extension is received in an opened end portion of the housing |28 and has a shaft 202 journaled therein. This shaft carries a cam follower or wheel 204 thereon which operatively engages a cam 206 which is detachably secured to the said shaft 64. Upon rotation of the shaft 64, the cam 206 is also rotated, thereby urging the cam follower 204 in a Vreciprocating manner. This in turn urges the carriage |50 in the same manner and also the torch |20 over the work piece I0.

Meansfor simultaneously urging the carriage in a return direction (as opposed to the direction of urging of the cam 206) and for maintaining the cam follower 204 against the surface of the cam 206, is supplied. The preferable means may be seen as a pair of conventional springs 208 and 2|0 respectively, which are secured to suitable perches l2| 2 and 2| 4. The s-aid perches 2|2 are secured to the substantially U-shaped bracket |48 and the perches 2|4 are operatively associated with the said housing |28. Through this expedient the torch |20 is moved in its travel to form undulations or deviations from the substantially circular orbit of travel.

Various gear ratios vmay be obtained in order to control the speeds of operation of both the generally circular movement of the torch and also the deviations from the general circle. The requisite and desired gear ratios realized from the use of a conventional transmission are readily ascertainable and by removing of certain of the gears on the platform l2 and substitution of other gears of different properties, another ratio variation may be realized. For convenience in such a change, the gears 34, 36, 38 and 42, may be supplied on-*a gear rack 220 for easy removal and substitution of another subassembly.

From the foregoing description of the elements including the operation and method, a clear understanding of the invention is deemed manifest. However, it is apparent that variations may be made without departing from the spirit of the invention.

Having described the invention, what is claimed as new is:

1. An apparatus for thermochemically cutting gears from -a sheet blank comprising a frame, a sleeve journalled in said frame, a shaft journalled in said sleeve, means for simultaneously rotating said sleeve and shaft at diiferent predetermined, selected speeds, a torch, means for attaching said torch to said sleeve, means operated by said shaft for moving said torch toward and from the longitudinal axis of said-sleeve in timedv plate.

3. The combination of claim 2 whereinl said torch moving means includes a cam secured to said shaft, a cam follower secured to said carriage, and means for resiliently biasing said car- A riage in a direction to yieldingly hold said cam follower against said cam.

' 4. A n apparatus for thermochemically cutting gears lfrom a sheet blank comprising a frame, a sleeve journalled in said frame, a shaft journalled in said sleeve, means for rotating said sleeve and shaft -at different predetermined, selected speeds, a torch, means, for attaching said torch to said sleeve, means operated by said shaft for moving said torch toward and from the longitudinal axis of said sleeve in timed rel-ation to the rotation of said sleeve, means responsive tothe position of travel of said sleeve and shaft for regulating the speed of said torch, said torch attaching means including a plate having a carriage associated therewith, means for limiting the travel l of said carriage onY said plate, said sleeve and shaft rotating means including a mechanical variable gear ratio transmission driven by said iirst mentioned means, means for rotating said sleeve associated with the driven side of said transmission and means for rotating said shaft associated with the driving side of said transmission, a rotary switch having a iirst element secured to said shaft and a second element actuated by said sleeve, switch cont-acts movable relative to each other and secured to said second element, conductors forming a circuit including `said motor and said contacts, a bypass conductor having a resistor in said circuit for supplying varied values of current to the motor in accordance with the relative positions of said switch contacts.

5. In an apparatus for thermochemically cut-r ting, a torch and a support therefor, means for moving said torch in a generally circular path, means for periodically imparting a traversing movement deviating said torch from its circular path, means for decreasing the speed of the torch during said traversingmovement, said means for moving said torch in a generally circular path including a motor attached to Vsaid support, a sleeve journalled in said support, means for drivingly connecting said motor and said sleeve, means for adjustably supporting said torch on said sleeve, said deviating means including a shaft in said sleeve having a cam thereon, means associated with said torch for engaging said cam to urge said torchin a travel devious to the generally circular path, a rotary circuit breaker including a first element attached to said sleeve 'and a, SlDIld element dttfhed t0 Said Shaft, C011- taets. on said .r-st element periodically engageable upon mutual rotation of the sleeve and. Shaft. an electrical circuit having said Circuit breaker and .motor therein, and means in Said, circuit. for bypassing current to vary the. speed. of the Said motor.

6- A gear cutter comprising a Support, a .first andy second shaft mounted for rotation in said erinnert, a motor means including a manually operable variable ratioV transmission drivinglir connected with said iirst shaft, said second shaft being rotated by said motor means, a switch in circuit with said motor means, means actuated by said second shaft periodically for rendering said ,switchy operative, a resistance in circuit with Said switehand said motor means decreasing the speed of said motor means and both of said shafts when said swfitch is rendered operative, a torch, means fixing said torch to Said first shaft for generally orbieal movement, and means carried by said .Second .shaft and said last mentioned means for moving said torch in a travel devious Vte the generally orbical travel, including a cam and a cam follower, and resilient means urging said cai-n follower against said cam.

DANIEL A. SCHROCK,

REFERENCES CITED The following references are of record in the le of this patent:V

UNITED STATES PATENTS 

